Apparatus for loading hotmix in a surge bin

ABSTRACT

Hotmix is continuously delivered by conveyor to the top of a surge bin, and is intermittently held back from dropping into the bin by a pulse feeder which continuously receives the hotmix and pulsingly discharges the hotmix to the surge bin. The feeder includes an open topped container with a central discharge opening which is intermittently opened and closed by pneumatically activated clam gates.

United States Patent 11 1 Rheinfrank, Jr.

[ 1 Dec. 11, 1973 [54] APPARATUS FOR LOADING HOTMIX IN A 3,182,8595/1965 Harris et al. 214/17 C X U G BIN 2,739,797 3/1956 Kemper 222/503X 0 3,378,171 4/1968 Eaton 214/17 R X [75] Inventor: Lamsou Rhe1nfrank,JKansas 3,438,520 4/1969 Williams 214/17 0 x City, Mo. [73] Assignee:Standard Havens Systems Inc., Primary P Glasgow, Mo. Att0mey-Lowe, Koker, K1rcher, Wharton and Bowman [22] F1led: Mar. 11, 1970 [21] Appl.No.: 18,651 [57] ABSTRACT Hotmix is continuously delivered by conveyorto the [52] U.S. Cl 214/17 C p of a surge and is intermittently d back f[51] Int. Cl. B65g 65/32 pp g into h in by a pulse e er hi h n inu- [58]Field of Search 214/17 R, 17 C, 17 CB; ously receives the hotrnix andpulsingly discharges the 222/503 hotmix to the surge bin. The feederincludes an open topped container with a central discharge opening [56]References Cited which is intermittently opened and closed by pneu-UNITED STATES PATENTS matically activated clam gates. 3,305,138 2/1967Plumb 214/17 C X 1 Claim, 6 Drawing Figures Ill i s l8 PAIENTED DEC! 1ms shaman 7 HUM, 1/ 2,

I N V E NTOR Lawson fi/M/h/mnk, J).

APPARATUS FOR LOADING HOTMIX IN A SURGE BIN BACKGROUND OF THE INVENTIONMany advances and improvements in the art of materials handling havedirectly contributed to increased production with decreased productioncosts. An aspect of this field to which this invention particularlyrelates is that of handling paving material, known in the trade ashotmix. The term hotmix broadly includes various grades of hot asphaltmixed with varying quantities of crushed rock, commonly known asaggregates. The aggregates vary from fine mixes of approximately onehalfinch size to coarse mixes of approximately 1% inch size.

In the past, one of the bottlenecks in paving construc tion had beentrucking the hotmix from the hotmix plant to the job site. In order todecrease the trucking expenses and also the waiting time of a truck atthe hotmix plant, temporarystorage and loading facilities for hotmixplants have been developed.

Typical loading equipment to which this invention relates includes aconveyor apparatus which continuously receives hotmix from the plant anddelivers it to a temporary storage or surge bin. Generally, this bin hasan upper portion and a lower cone-shaped portion with a centraldischarge opening. The surge bin is supported on stilt legs whichprovide a drive through in which trucks can be positioned under thedischarge opening to receive a load of hotmix.

This type of temporary storage operation has been successfully used toreduce truck waiting time since a full truck load of hotmix is availablewhen a truck arrives from the job site. In addition, by smoothing outloading times and enabling the orderly delivery of hotmix from the plantto the job site, fewer trucks are required for paving construction.

The maximum time that hotmix is held in the surge bin is 12 hours, butin normal operation, the hold-up time is less than 2 to 3 hours.Therefore, the bin is not generally considered a storage device per se,but it may be adapted for such uses by installing insulation and heatingequipment to prevent cooling and subsequent hardening of the hotmix.

Although this operation has many advantages, there is a problem whichhas developed from its use. The conveyor system used to continuouslysupply hotmix from the plant to the surge bin typically discharges thematerial into the center of the surge bin. As the bin continues to fillin this manner, the hotmix forms a cone-shaped pile and the coarseaggregates tend to separate from the asphalt and move outwardly to thebase of the pile along the periphery of the bin. This phenomena iscommonly termed segregation and results in an uneven distribution ofaggregates in the hotmix.

SUMMARY OF THE INVENTION The primary object of this invention is toprovide a method and apparatus to substantially reduce segregation ofthe aggregates when hotmix is discharged into a surge bin. To accomplishthis, hotmix is continuously fed to the upper end of the bin but isintermittently interrupted from free fall toward the bottom of the binin pulses. Therefore, most simply stated, this invention transforms thenormally continuous loading operation into a pulse-type operation whichprevents segregation of the aggregates within the surge bin.

Another object of the invention is to provide an apparatus which can beactivated to pulsingly discharge hotmix to a surge bin by a variety ofcontrol means. When equipped with standard manual or automatic controlmeans, the apparatus may be activated on the basis of total weight ofthe hotmix, total volume of the hotmix, or preselected time intervals.

Another object of the invention is to provide an apparatus of thecharacter described which can be easily installed on either permanent orportable surge bins.

Another object of the inventionis to provide an apparatus of thecharacter described which is rugged in construction and extremelydependable in operation, functioning virtually trouble-free while stillhandling a material which is characteristically troublesome.

Other and further objects of the invention, together with the featuresof novelty appurtenant thereto, will appear in the course of thefollowing description.

DESCRIPTION OF THE DRAWINGS In the accompanying drawings, which form apart of the instant specification and are to be read in conjunctiontherewith, and in which like reference numerals are used to indicatelike parts in the various views:

FIG. 1 is a generally schematic view of a surge bin, continuous conveyorand pulse feeder constructed according to and for carrying out themethod of the invention;

FIG. 2'is an enlarged side elevational view of the pulse feeder andfragmentary portions of the supports therefor with the clam gates shownin an opened position;

FIG. 3 is a side elevational view of the side of the feeder whichreceives the continuous conveyor;

FIG. 4 is a plan view of the feeder mounted on the surge bin;

FIG. 5 is a side elevational view along line 5-5 of FIG. 3 in thedirection of the arrows; and

FIG. 6 is a schematic diagram of the pneumatic sys tem used to activatethe clam gates.

Referring to the drawings in more detail, FIG. 1 illustrates the surgebin, continuous conveyor and pulse feeder in the normal operatingrelationship at a hotmix plant. The feeder, generally designated numeral10, surmounts a surge bin, generally designated numeral 1 l, and iscontinuously fed by an inclined conveyor 12, only the upper portion ofwhich is shown. The lower end of the conveyor 12 (not shown) receiveshotmix from the plant and transports the material to the upper end whereit is continuously discharged from a dumping spout 13. Such a conveyorparticularly useful in the instant invention is described in mycopending application Inclined Drag Conveyor for Hot Asphalt Mix and theLike, Ser. No. 846,344, filed July 31, 1969.

The surge bin 11 includes an upper cylindrical portion 14 terminating atits lower end with a frustoconical portion 15 which has a centralopening 16 at the bottom from which hotmix can be discharged to loadingtrucks. The surge bin 11 is supported above the ground 17 by a pluralityof stilt legs 18 which form a drive through 19 in which trucks orsimilar receiving equipment can be positioned. The legs 18 areinterconnected by horizontal members 20 at the upper ends thereof. Alsoattached to the upper ends of the legs 18 are bin support members 21,attached in turn to vertical members 22 which extend throughout theentire 3 height of the cylindrical portion 14 to provide additionalsupport and rigidity.

At the upper end of the vertical members 22 are connected horizontalmembers 23 and 24 which are transversely disposed across the top of thecylindrical portion 14 of the surge bin 11, as viewed in FIG. 4. Thesemembers 23 and 24 provide the basic supporting structure for the feedernow to be described in detail.

Although much smaller in size, the feeder 10 is structurally similar tothe surge bin 11 itself. The feeder 10 includes an open topped, uppercylindrical portion 25 surmounting a lower frusto-conical portion 26which terminates in a discharge opening. Affixed to the upper edge ofthe cylindrical portion 25 is a flange-type lip 27 which can be fittedwith a rain cover (not shown) during inclement weather.

As viewed in FIGS. 2 and 4, the feeder 10 is concentrically disposed atthe upper end of the surge bin 11 and is supported on one side by anupright member 28 attached to the horizontal member 23. Sloped bracingmembers 29 interconnect members 23 and 28 to provide additional supportfor the vertical member 23.

On the opposite side of the feeder 10 (FIG. 3), a pair of uprightmembers 30 extend from the horizontal member 24 adjacent the side wallof the cylindrical portion 14. Near the upper ends of the uprightmembers 30 is attached a horizontal, conveyor supporting rail 31 whichis disposed near the bottom of an opening 32 in thecylindrical portion14. A stub support 33 is also attached to the horizontal member 24 andthe lower edge of the cylindrical portion 14 to support the feeder 10.

At the lower end of the feeder 10 is a pair of clam shell gates 34. Eachgate 34 is pivotally suspended near the upper edge of the conicalportion on opposite sides thereof by bosses 35 which receive pivot bolts36.

At the outer, lower edge of each gate is a centrally attached bracket 37which is pivotally connected to the piston rod 38 of the pneumaticcylinder 39. The upper end of the pneumatic cylinder 39 is pivotallyconnected to a bracket assembly 40 rigidly affixed to the side wall ofthe cylindrical portion 14.

Above each bracket assembly 40, a hoisting connection 41 is rigidlyattached to facilitate installation or removal of the feeder 10.

With the piston rods 38 of the pneumatic cylinders 39 fully extended,the gates 34 mate to provide a closure for the discharge opening of thefrusto-conical portion 15 as viewed in FIG. 3. When the piston rods 38are retracted into the pneumatic cylinders 39, the gates are pivotallypulled apart and material contained in the cylindrical and conicalportions 14 and I5 falls through the discharge opening as viewed in FIG.2. In this connection, I find it beneficial to construct the conicalportion 15 using a slope of approximately 70 to insure all material willbe discharged easily. It is also helpful to provide a quick-actingpneumatic (or hydraulic) system for the cylinders 38 as rapid action ofthe gates assists in achieving the objects of the invention. Likewise,mated gear teeth 34a at the upper ends of the gates 34, as viewed inFIG. 2, insure failsafe operation in the event of failure of eithercylinder 39.

FIG. 6 illustrates a typical pneumatic control system for connecting thecylinders 39 in parallel to achieve the previously mentioned function.Extension lines 42 are connected to fittings 43 of each cylinder 39 andare also connected via a T-fitting 44 to a line 45 from a pneumaticcontroller 46. Likewise, retraction lines 47 are connected to fittings48 of each cylinder 38 and are also connected via a T-fitting 49 to aline 50 from the hydraulic controller 46. Two adjustable automatictimers 51 and 52 connected to the controller 46 provide the signals toactivate the opening and closing cycle of the clam gates 34 as well asthe hold time.

In operation, the pulse feeder constructed in accordance with theprincipals previously described, is utilized in the following manner.

The feeder 10 surmounts the surge bin 11 as viewed in FIG. 1. Thecontinuous conveyor 12 is oriented to permit the upper end to engage thesupporting rail 31 with the dumping spout 13 as directed into the centerof the feeder 10. The lower end of the conveyor 12 is positioned in thehotmix plant to continuously receive hotmix therefrom.

As the conveyor 12 continuously discharges hotmix into the feeder 10,the clam gates 34 are closed with the piston rods 38 extended from thepneumatic cylinders 39. When a sufficient amount of hotmix is deliveredto the feeder 10, the pneumatic cylinders 39 are activated to retractthe piston rods 38, thus opening the clam gates 34 and discharging theentire load of hotmix into the surge bin 11. Once the hotmix isdischarged, the pneumatic cylinders 39 are again activated to extend thepiston rods 38 and close the clam gates 34.

There are a variety of control systems available to determine theopening and closing cycle of the clam gates. Such control systemsinclude operating on predetermined time intervals, operating by thetotal weight of the load received by the feeder, or the total volume ofhotmix received by the feeder. Since the conveyor provides asubstantially steady state flow of hotmix, l have found that anautomatic control system which opens the gates at preselected timeintervals is satisfactory for use in conjunction with this invention.

With this invention, a loading operation which was previously continuoushas been transformed into pulsetype loading. By discharging a relativelylarge amount of hotmix to the surge bin at one time, the problem ofsegregation is simply no longer a problem.

From the foregoing, it will be seen that this invention is one welladapted to attain all of the ends and objects hereinabove set forthtogether with other advantages which are obvious and which are inherentto the structure.

It will be understood that certain features and subcombinations are ofutility and may be employed without reference to other features andsubcombinations.

Since many possible embodiments may be made of the invention withoutdeparting from the scope thereof, it is to be understood that all matterherein set forth or shown in the accompanying drawings is to beinterpreted as illustrative and not in a limiting sense.

Having thus described my invention 1 claim:

1. In combination with a continuous conveyor and a surge bin,

an open topped container surmounting said surge bin and concentricallyaligned therewith, said container being of relatively smaller size thansaid surge bin and including an upper cylindrical portion and afrusto-conical portion constructed with a slope in the range of to andhaving a discharge opening at the lower end thereof; movable closuremeans associated with said container and operable to close saiddischarge opening, said closure means including a pair of clam open andclose said discharge opening; and gates, each of said gates pivotallysupported at opa supporting rail attached to the upper cylindricalposite sides of said container; portion of said container and operableto support pneumatic cylinder means connected to said clam the end ofsaid continuous conveyor.

gates to intermittently move said gates and thereby 5

1. In combination with a continuous conveyor and a surge bin, an opentopped container surmounting said surge bin and concentrically alignedtherewith, said container being of relatively smaller size than saidsurge bin and including an upper cylindrical portion and afrusto-conical portion constructed with a slope in the range of 60* to80* and having a discharge opening at the lower end thereof; movableclosure means associated with said container and operable to close saiddischarge opening, said closure means including a pair of clam gates,each of said gates pivotally supported at opposite sides of saidcontainer; pneumatic cylinder means connected to said clam gates tointermittently move said gates and thereby open and close said dischargeopening; and a supporting rail attached to the upper cylindrical portionof said container and operable to support the end of said continuousconveyor.